The present invention relates generally to medical catheters and relates more particularly to medical catheters of the type having an internal bolster disposed at one end of said medical catheter for retaining said end of said medical catheter within a patient.
Certain patients are unable to take food and/or medications transorally due to an inability to swallow. Such an inability to swallow may be due to a variety of reasons, such as esophageal cancer, neurological impairment and the like. Although the intravenous administration of food and/or medications to such patients may be a viable short-term approach, it is not well-suited for the long-term. Accordingly, the most common approach to the long-term feeding of such patients involves gastrostomy, i.e., the creation of a feeding tract or stoma between the stomach and the upper abdominal wall. (A less common approach involves jejunostomy, i.e., the creating of a feeding tract or stoma leading into the patient's jejunum.) Feeding is then typically performed by administering food through a catheter or feeding tube that has been inserted into the feeding tract, with one end of the feeding tube extending into the stomach and being retained therein by an internal anchor or bolster and the other end of the feeding tube extending through the abdominal wall and terminating outside of the patient.
Although gastrostomies were first performed surgically, most gastrostomies are now performed using percutaneous endoscopy and result in the implantation in the patient of a feeding tube/internal bolster assembly (said feeding tube/internal bolster assembly also commonly referred to as a percutaneous endoscopic gastrostomy (PEG) device). Two of the more common percutaneous endoscopic techniques for implanting a PEG device in a patient are “the push method” (also known as “the Sacks-Vine method”) and “the pull method” (also known as “the Gauderer-Ponsky method”). Information regarding the foregoing two methods may be found in the following patents, all of which are incorporated herein by reference: U.S. Pat. No. 5,391,159, inventors Hirsch et al., which issued Feb. 21, 1995; U.S. Pat. No. 5,167,627, inventors Clegg et al., which issued Dec. 1, 1992; U.S. Pat. No. 5,112,310, inventor Grobe, which issued May 12, 1992; U.S. Pat. No. 4,900,306, inventors Quinn et al., which issued Feb. 13, 1990; and U.S. Pat. No. 4,861,334, inventor Nawaz, which issued Aug. 29, 1989.
According to the push method, one end of an endoscope is intubated (i.e., inserted) into a patient's mouth and is passed through the esophagus into the stomach. After distension of the stomach by inflation, an entry site on the abdomen is identified using the endoscope for transillumination, and an incision is made by passing the tip of a needle coupled to an outer cannula through the abdominal and stomach walls and into the stomach. One end of the outer cannula remains outside of the body and acts as a stop to limit insertion of the needle and outer cannula into the stomach. A snare is inserted into the stomach via the endoscope and is looped over the inserted end of the needle. The snare is then “walked” up the needle until the outer cannula is snared. The snared cannula is then pulled externally to tack the cannula to the stomach and, in turn, to secure the stomach wall to the abdominal wall. The needle is then removed from the patient while keeping the cannula in place. A first end of a flexible guidewire (also known in the art as a “pushwire”) is then passed through the cannula and into the stomach where it is grasped by the snare, the second end of the guidewire remaining external to the patient. The endoscope and the snare are then withdrawn from the mouth of the patient to deliver the first end of the guidewire.
A push-type catheter implanting assembly is then inserted over the first end of the guidewire and is pushed over the guidewire towards its second end. The push-type catheter implanting assembly typically comprises a gastrostomy feeding tube, the gastrostomy feeding tube having a dome-shaped internal bolster disposed at its trailing end and having a tubular dilator serially connected to its leading end. The gastrostomy feeding tube and the internal bolster are typically made of a soft, biocompatible material, like silicone rubber, and typically form a unitary structure. The dilator, which tapers in outer diameter from its trailing end to its leading end, is typically made of polyethylene or a like material which is stiffer than silicone but which still possesses some flexibility. Advancement of the push-type catheter implanting assembly over the guidewire continues until the front end of the dilator reaches the cannula and pushes the cannula out through the abdominal wall of the patient. The front end of the dilator is then pulled through the abdominal wall until the front end of the gastrostomy feeding tube emerges from the abdomen and, thereafter, the internal bolster at the rear end of the gastrostomy feeding tube engages the stomach wall. The guidewire is then removed from the patient. The clinician then re-intubates the patient with the endoscope and uses an optical channel in the endoscope to inspect whether the internal bolster is properly seated in the stomach.
If the internal bolster is properly placed against the stomach wall, a length of the externally-extending portion of the implanted gastrostomy feeding tube is then typically cut and removed from the implanted tube to reduce the externally-extending portion of the tube to a desired length (typically about 4-6 inches). (The removal of the leading end of the gastrostomy feeding tube also results in the removal of the dilator, which is connected thereto.) An external bolster is typically secured to the remaining externally-extending portion of the feeding tube to engage the abdomen in such a way as to prevent longitudinal movement of the feeding tube into the stomach. Additionally, a “Y-port” adapter is typically attached to the external end of the feeding tube, the Y-port adapter being adapted to receive a pair of connector tips through which food and/or medications may be dispensed. In addition, a detachable locking clip is typically secured to the implanted feeding tube at a point between the external bolster and the Y-port adapter to prevent gastric fluids from escaping through the proximal end of the feeding tube when the feeding tube is not in use.
The pull method is similar in some respects to the above-described push method, the pull method differing from the push method in that, after the cannula is snared and the needle is removed therefrom, a looped first end of a suture (also known in the art as a “pullwire”) is inserted through the cannula and into the stomach where it is grasped by the snare, the second end of the suture remaining external to the patient. The endoscope and the snare are then withdrawn from the mouth of the patient to deliver the first end of the suture. The first end of the suture is then coupled to the leading end of a pull-type catheter implanting assembly, the pull-type catheter implanting assembly typically comprising a gastrostomy feeding tube having an internal bolster integrally formed at its trailing end and a plastic fitting attached to its leading end. The plastic fitting typically has a barbed rear portion mounted within the leading end of the feeding tube and a conical front portion that serves as a dilator, said conical front portion tapering in diameter from the leading end of the feeding tube to a front tip. A wire loop is fixed to the front tip of the plastic fitting, the first end of the suture being tied to the wire loop. Using the second end of the suture, the pull-type catheter implanting assembly is then pulled retrograde through the patient until the gastrostomy feeding tube emerges from the abdomen of the patient and the internal bolster engages the stomach wall of the patient. Next, as is the case in the push method, the clinician then re-intubates the patient with the endoscope in order to visually inspect the placement of the internal bolster within the stomach. If the bolster is properly seated in the stomach, the externally-extending portion of the implanted gastrostomy feeding tube is then typically cut to a desired length and one or more of an external bolster, a Y-port and a clamp are attached to the feeding tube.
In addition to the above-described endoscopic techniques for implanting PEG devices, there also exist direct percutaneous techniques.
Typically, such direct percutaneous techniques involve (i) inserting an endoscope into the patient and, through transillumination, identifying a desired insertion site; (ii) using sutures or T-fasteners, placed one at a time, to secure the abdominal wall to the stomach wall in a plurality of locations surrounding the future insertion site; (iii) using a scalpel to make an incision at the insertion site; (iv) using a series of dilators to enlarge the insertion site opening until said opening is large enough to pass therethrough the internal bolster at the distal end of a gastrostomy tube; and (v) sliding an external bolster over the proximal end of the gastrostomy tube down to skin level over the T-fastener wires or sutures.
Another type of direct percutaneous technique is disclosed in U.S. Pat. No. 6,030,364, inventors Durgin et al., which issued Feb. 29, 2000, and which is incorporated herein by reference. In this patent, there is disclosed a method and apparatus for the percutaneous placement of gastro-intestinal tubes, the apparatus comprising a longitudinal penetration device; a hollow, tapered dilator; and a sheath having a central lumen extending therethrough. The penetration device is placed within the sheath, pushed distally to penetrate the target organ, and then removed from the sheath. After the penetration device is removed, the dilator is inserted into the central lumen of the sheath until it penetrates the target organ, so that the sheath and the penetration are radially dilated as the dilator passes through the sheath. The sheath is then pulled in the proximal direction to counter-balance the distal insertion force. A gastro-intestinal tube is inserted into the hollow center, and pushed distally until it exits the distal end of the dilator. The dilator and sheath are then removed from the target organ.
Still another type of direct percutaneous technique is disclosed in U.S. Pat. No. 6,402,722, inventors Snow et al., which issued Jun. 11, 2002, and which is incorporated herein by reference. In this patent, there is disclosed an apparatus and method for percutaneously placing gastrostomy tubes. The method enables percutaneous placement through an existing penetration, as well as placement where no penetration exists. The apparatus comprises a gastrostomy tube having an internal bolster which can be manipulated such that it has a reduced lateral extent; an axially-extending hollow sleeve which can surround the bolster to hold it in a position of reduced lateral extent; and a rip-cord capable of tearing the sheath. In a preferred embodiment, the internal bolster is folded to have a smaller diameter, the sleeve is placed over the bolster and shrunk down to a smaller diameter. The rip-cord runs distally along the outside of the tube, between the sleeve and the internal bolster, wraps over the distal end of the sleeve and runs proximally along the length of the tube. The replacement tube can then be pushed through a stoma. Once in place, the rip cord is pulled to tear away the sleeve, thereby allowing the bolster to revert to its original lateral extent.
Still yet another type of direct percutaneous technique is disclosed in U.S. Published Patent Application No. US-2004-0059293-A1, which was published Mar. 25, 2004, and which is incorporated herein by reference.